Gel Frames

The number used in blubs like PAR, and MR, and other reflector bulbs stands for 1/8 inches.

So, MR-16 is 2 inches, PAR-64 is 8 inches.

So no, there is no difference,

 

arent most PAR gel frames hexagonal?

 

The rule of thumb regarding lamp sizes does not apply to gel frames, as it is completely dependant upon the maker of the PAR or Fresnel. While you can use the formula for figuring bulb diameters, you cannot accurately find the gel frame size.

For example;


PAR 16 is 3.0 inch gel frame
PAR 20 is 3.25 inch gel frame - 2.375 inch opening
PAR 30 is 4.375 inch
PAR 36 is 6.25 inch
PAR 38 is either 6 inch or 7.50 inch gel frame
PAR 46 is either 6.25 inch or 7.5 inch
PAR 56 is either 7.5 inch or (MBT) 9 inch
PAR 64 is 10.0 inch

Also- most gel frames are square, while budget frames are hexagonal. The yield per sheet of aluminum/sheet metal is higher when arranging for this odd size.